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Cyclic Service
Posted: 19 Oct 2026, 17:52
by Guest
How to identify which pressure vessels are in cyclic service to make sure they have a separate inspection plan /written scheme?
Re: Cyclic Service
Posted: 20 Oct 2026, 17:55
by ben
API 510 11th edition under 3.1.15 clearly defines cyclic service as:
"Refers to service conditions that could result in cyclic loading and produce fatigue damage or failure (e.g.,
cyclic loading from pressure, thermal, and/or mechanical loads). Other cyclic loads associated with vibration
could arise from such sources as impact, turbulent flow vortices, resonance in compressors, and wind, or any
combination thereof"
Re: Cyclic Service
Posted: 22 Oct 2026, 06:04
by arcpro
Regarding the inspection plan or written scheme development, API 572 under 9.3.13, "External Metal Surfaces" recommends to inspect vessels in cyclic service at external supports using either PT or MT testing for fatigue cracking. This is what should be made part of the written scheme as-is.
Also if you refer to API 572, para 9.4.5.5, it is stated that welded seams in vessel shells should be closely checked when the service is cyclic that may promote cracking. Better to get that part of the written scheme also.